以下属于无效的民事行为的是()。
A.10岁小学生创作一副美丽的图画
B.8岁的小学生购买笔记本电脑一台
C.5岁的儿童获得奖励
D.12岁中学生购买课本
参考答案:B
Fair and(1)competition in government procurement around the world is good business and good public policy. Competitive pricing, product (2)and performance improvements result from competitive practices and help ensure that government authorities get the best (3)for the public they serve.
3.见题干()
A. help
B. server
C. value
D. policy
减小铰刀主偏角可减小切削层厚度,使切削平稳,能获得较细的()